Maryam Rostami; Ali Salajegheh; Forood Sharifi; Arash Malekian; TAYYEBEH MESBAHZADEH
Abstract
AbstractPrecipitation plays an important role in climatic, water, energy and biogeochemical cycles. Several global and regional data sets currently provide historical estimates of this variable over Iran, including the MWEP and WFDEI forcing datasets and production of some institutions such as MOHC, ...
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AbstractPrecipitation plays an important role in climatic, water, energy and biogeochemical cycles. Several global and regional data sets currently provide historical estimates of this variable over Iran, including the MWEP and WFDEI forcing datasets and production of some institutions such as MOHC, SMHI and IITM. All these datasets provide data with different resolutions based on gage stations, satellite Images and models output. In this study, we do an inter comparison between these data sets during 1990- 2008. We also validate all ten data sets against independent ground station observations over 30 second-order basins of Iran. MSWEP and WFDEI have an acceptable compatibility with observational data on different spatial and temporal resolutions. RMSE and Bias are 5.68, 6.34 and 0.58, 2.75 for these two datasets during 228 months, respectively. However, it is needed that MSWEP improves in the western and northwestern parts of the country and WFDEI in June and September months. Our findings in this research provide valuable guidance for a variety of stakeholders, including rainfall- runoff and land-surface modelers, watershed management studies and data providers.
Abazar Esmaili; Mohammad Golshan
Abstract
Watersheds are a vast area with different conditions that simulation and studying the processes of runoff and sediment production in these area are critical for managing and maintaining resources. The Kozatopraghi watershed with an area of 766 km2 is located in the south and upstream of the Garesou basin, ...
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Watersheds are a vast area with different conditions that simulation and studying the processes of runoff and sediment production in these area are critical for managing and maintaining resources. The Kozatopraghi watershed with an area of 766 km2 is located in the south and upstream of the Garesou basin, Ardebil province. Between the hydrological models, based on the capabilities of the SWAT model, this model was used to simulate the hydrological processes of the area in sub watershed scale. Also, for a more accurate examination the rainfall simulator was used in the hydrologic response units (HRUs), the obtained results were generalized to the sub watershed scale. The results of SWAT model were assessment with statistical parameters R2, NSE and RMSE. In the calibration and validation periods these coefficients for simulation runoff obtained 0.8-0.74, 0.71-0.69 and 0.32-0.33, respectively, and for simulation sediment yield obtained 0.75-0.66, 0.72-0.64 and 35.27-26.39, respectively. Assessment the obtained results of rainfall simulator showed that Loamy soils, located in 8 HRUs have high effect in sediment yield production. The maximum runoff and sediment yield by rainfall simulator and SWAT model were observed in sub watersheds 13 and 1, that indicating poor and inappropriate conditions in these subwatersheds. Comparing the study methods showed that the SWAT model have better performance than rainfall simulator for simulation runoff. Also, the estimated sediment yield by this model is lower than rainfall simulator that is close to observed values.
Shahab oddin Zarezade Mehrizi; Asadollah Khoorani; Javad Bazrafshan; Ommolbanin Bazrafshan
Abstract
Gamasiab River is one of the five main branches of the Karkheh River and plays a basic role in preserving the life and ecosystem of the region. The first step in the adoption of proper and sustainable methods for managing the water resources of the Gamasiyab river is to gain continuous knowledge of the ...
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Gamasiab River is one of the five main branches of the Karkheh River and plays a basic role in preserving the life and ecosystem of the region. The first step in the adoption of proper and sustainable methods for managing the water resources of the Gamasiyab river is to gain continuous knowledge of the quantitative and qualitative status of the water as well as its variations. The use of hydrological models is common to simulate quantitative and qualitative processes associated with the water cycle. One of the models that is widely used in the international level is the SWAT model. In this research, we evaluated the efficiency of SWAT model in simulation of Gamasiyab river flow. For running this model requires a DEM, soil map, land use map and slope classification. Initially, discharge data in daily step at Polchehr Hydrometric Station was calibration (1977-1995 AD) and then validation (1996-2005 AD) by using precipitation data of two synoptic stations and three weather stations and minimum and maximum temperature of two synoptic stations. Statistical coefficients including Nash-Sutcliff coefficient, R2, P-factor and R-factor for calibration period were 0.71, 0.73, 0.79, 1.36 respectively and for validation period were 0.57, 0.61, 0.71 and 1.34 respectively. These results indicate that the SWAT model has the ability to simulate the Gamasiyab River discharge and researchers can use this model to apply management scenarios in short time and low cost for better decision making.
heydar ebrahimi; Alireza Moghaddam Nia; Haji Karimi
Abstract
The runoff simulation in a watershed provides insight on the processes affecting runoff generation and the stream flow characteristics like spatial and temporal variability of stream flow. This insight helps managers and planners in informed decision-makings on water resources management and planning. ...
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The runoff simulation in a watershed provides insight on the processes affecting runoff generation and the stream flow characteristics like spatial and temporal variability of stream flow. This insight helps managers and planners in informed decision-makings on water resources management and planning. The objective of this study is to compare the performances of the complex SWAT model and the simple IHACRES model for simulating runoff in the Doiraj river basin, Ilam province. For this purpose, SWAT model due to having many parameters affecting stream flow and the use of GIS, and IHACRES model due to the low and easy access data requirements, are very practical. In this study, the data over a period from 1994 to 2004 and the statistical criteria of R2, bR2, and NS were used to evaluate performances of IHACRES and SWAT models. For IHACRES model, values of R2, bR2 and NS were estimated equal to 0.34, 0.112 and 0.33, respectively for calibration period and values of 0.47, 0.235 and 0.43, respectively for validation period. In addition, for SWAT model, the coefficients were estimated equal to 0.41, 0.314 and 0.12 respectively, for calibration period and values of 0.68, 0.632 and 0.56, respectively for validation period. Final results of this study showed higher performance of SWAT model relative to IHACRES model for simulating daily runoff in Doiraj river basin and can be used to simulate runoff in the watersheds with limited data and similar natural conditions.
TAYYEBEH MESBAHZADEH
Abstract
This research was done in order to submit a model for salinity map made with TM satellite data and salinity values in a Buienzahra. The necessary processings such as principal component analysis and producing of different indices was done on the main bands. The 38 soil samples using random sampling (with ...
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This research was done in order to submit a model for salinity map made with TM satellite data and salinity values in a Buienzahra. The necessary processings such as principal component analysis and producing of different indices was done on the main bands. The 38 soil samples using random sampling (with 10×10 km dimension) from different horizons were designed and performed on the study area. The position of each node was registered with global positioning system (GPS), and the surface electric conductivity of samples was measured using EC meter instrument in soil saturation extract. Correlation between spectral values (main bands, produced indices) with electrical conductivity values were investigated for 80% of the samples. The regression analysis of ECe showed that there is a significant correlation between ECe with spectral data in all of main bands and with BI, NDMI, SI1, SI2, SI3 indices in 99% levels. The accuracy assessment of estimations using validation 20% samples was done. Results showed the produced ECe model could predict the soil salinity with ME and RMSE of 0.08 and 2.53 dS/m respectively. At finally, Salinity map with different salinity classes ( 0-2, 2-4, 4-16, 16-32, 32< dS m-1) was produced.
Zohreh Alijani; Fereydoun Sarmadian; Seyed Rouhollah Mousavi
Abstract
Today, extensive improvements in fields of soil mapping have increased the purity and accuracy ofsoil maps. Usual mapping methods moreover depend on skills and experience of surveyor inidentifying and delineating the boundaries, also need the high cost and time consuming that face thesoil mapping with ...
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Today, extensive improvements in fields of soil mapping have increased the purity and accuracy ofsoil maps. Usual mapping methods moreover depend on skills and experience of surveyor inidentifying and delineating the boundaries, also need the high cost and time consuming that face thesoil mapping with restrictions. In this study, aerial photographs with 1/40000 scale were used in orderto preparation of the initial interpretive map and determination of sample region. Then, the numbers of24 profiles were described in determined units. After sampling and necessary physicochemical tests,soil map of Kouhin (Qazvin) was prepared and accuracy of map was calculated in two methods in alllevels of taxonomy. The first method was formation of error matrix and calculation of kappa index andsecond was comparison the geopedological map with described profiles and evaluation the results ofeach. Then a part of a geopedological map that had overlapping with map prepared by usual methodwas compared with this map. Results showed the overall accuracy of 67.5, 90.5 and 98.5 percent inlevels of family- subgroup and great group- suborder and order of soil for geopedological methodrespectively.
Akram Arefi Asl; Ali Najafinejad; Farshad Kiani; Abdolrassoul Salmanmahiny
Abstract
Runoff and sediment measurement is difficult in mountain watershed because of many different problems such as time and financial limitations. So using simulation model is necessary in this regard. Accuracy and precision evaluation of models for different watershed of Iran is necessary. The aim of this ...
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Runoff and sediment measurement is difficult in mountain watershed because of many different problems such as time and financial limitations. So using simulation model is necessary in this regard. Accuracy and precision evaluation of models for different watershed of Iran is necessary. The aim of this study was the evaluation of SWAT model efficiency in simulation of runoff and sediment yield in Chelchay watershed in Golestan province, Iran and also calibration and validation of SWAT. SUFI2 algorithm was used for calibration and validation. Nash-Sutcliff for calibration period (2001-2005) and validation period (2006-2009) for average daily discharge was 0.5 and 0.4 respectively and for sediment concentration was 0.71 and 0.92 that is good according to past research results. Because SWAT is complex and integrated model and can be used as a management tool in watershed management so it is suggested that it would be used for evaluation of management activities effects in Chelchay watershed.
